Two new books wrestle with the issue of why readers' trust in the media has plummeted, writes Denis Muller in his review of the books 'Rupert Murdoch: an investigation of political power' by David McKnight, published by Allen and Unwin, Sydney, 2012, and 'Why Americans hate the media and how it matters' by Jonathan M. Ladd, published by Princeton University Press, Princeton, 2012.